Your breathing rate is 12 breaths/minute; your tidal volume is 500 mL; your vital capacity is 4700 mL; and your dead air space is 150 mL. Your alveolar ventilation rate is mL/min.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

i think that it is c, d, and e, hope this